An arm of a bicycle is 16cm long. It has a pedal at one end, attached to a sprocket ( the toothed disk around which the chain moves) of 22cm diameter. A cyclist riding this bike increases her pedalling rate from 50.rpm to 80.rpm in 8,0s.What lenghth of chain passes over the top of the sprocket during this interval? What is the angular speed of the rear sprocket after 8,0s if its radius is 5,5cm?